Whey is also called “milk serum,” and a large amount of whey is produced in the process of cheese production as a by-product. In the process of cheese production, a fungus, an acid or the like is added in milk to cause reaction therebetween, whereby a solid content called “curd,” i.e., an aggregate of casein protein is separated from a liquid portion called “whey” containing proteins most of which are whey proteins, minerals and lactose.
While whey has been mostly discarded in the past, whey began to receive recognition as a highly nutritious food with high proteins and low fats.
Due to its rich nutritions, whey easily deteriorates in quality. Hence, whey is dehydrated to be in a powdery form and is distributed in the form of whey powder.
That is, a whey protein concentrate in which proteins are concentrated while lactose and ash concentrations are decreased by removing lactose and other components, which are contained in whey in addition to proteins, from whey through, for example, ultrafiltration, or a protein-concentrated whey powder that is made by dehydrating such whey protein concentrate is sold on the market and used in production of infant foods as a protein source, in production of other various foods as an ingredient, and the like.
Patent Literature 1 discloses a technique for fractionating proteins from whey, where whey or concentrated whey obtained through ultrafiltration is passed through a column packed with an anion exchanger without adjusting the pH of the whey to effect the adsorption of (β-lactoglobulin to the anion exchanger, and the adsorbed β-lactoglobulin is eluted with a salt solution.
Patent Literature 2 discloses a technique for producing a protein concentrate from whey, where lactose is removed as permeate (extracted lactose, minerals) at the whey ultrafiltration step, the ultrafiltered whey retentate is subjected to heat treatment to cause about 50% or more and 90% or less in total of proteins in whey to denature, and the heat-treated whey is concentrated to produce a whey protein concentrate.